1. Field of the Invention
This invention relates to compositions for topical application of pharmaceutical compounds. Specifically, the invention relates to topical medicinal spray compositions, their use and films formed upon use. The compositions may be used to treat a variety of disorders.
2. Background of the Invention
Many delivery systems for the topical application of pharmaceutical compounds are currently available and include lotions, creams, gels, ointments, transdermal patches and sprays. The choice of delivery system usually depends upon the desired pharmacokinetic profile of the drug, for example, whether immediate or sustained release is required. Many of these systems suffer from occlusion problems and may cause skin irritation. For example, many compounds, including hormonal drugs, are conventionally delivered using a transdermal patch. These patches comprise an occlusive backing membrane which often results in local skin irritation. A further disadvantage of transdermal patches is that percutaneous penetration of the drug is often poor.
The problem of skin irritation associated with transdermal patches is not as pronounced when topical spray formulations are used. For example, British Patent Specification No. 1,372,721 discloses a container of antiseptic for the topical treatment of burns and scalds, containing a topically acceptable antiseptic active agent against Pseudomonas aeruginosa, a pressuring agent and at least one surfactant admixed with water. The container comprises an outlet, and valve means operable to allow discharge of the contents of the container through the outlet in the form of a foam which is effective in the control of Pseudomonas aeruginosa at the site of a burn or scald. U.S. Pat. No. 4,534,958 describes and claims “a sprayable aerosol foam treatment composition which is a liquid in the aerosol container and forms a gel upon application to the skin”. The composition in U.S. Pat. No. 4,534,958 comprises water, propellant, volatile solvent, a polyoxyethylene copolymer whose function is not described, and optionally a burn treatment agent and one or more adjuvants. The composition is used “for treating living skin”.
However, conventional topical spray formulations tend to remain at the application site for only a short time. For example, they are easily rubbed off. As a result, the medicament to be absorbed through the skin is only available transiently. By contrast, medicament in a transdermal patch is potentially available for as long as the patch remains in place.
This invention provides advantages not previously realized. Specifically, the invention provides a composition for the topical application of pharmaceutical compounds without causing occlusion problems or skin irritation. Moreover, the inventive compositions remove the need for an adhesive patch. The invention further provides a topically applied composition that may remain as a breathable film on the skin for an extended period of time.